How about respecting almost 2000 years of history, perseverance, and influence across the globe at the height of the British Empire? London is still a (positive) reference for many, which is a strength, too. I know we don't talk about Empire now, it's a dirty word, but London was the symbol of civil society for centuries, and will continue to be long after some mayor has passed through.
Not ranting, just don't see the benefits of this when London is already a strong city in its own right.